Oil is used during manufacturing process, but parts designed for oxygen is specifically cleaned for oxygen use and Compressed Gas Association (CGA) provides guidelines on the process.
A PFPE lube like Christo-Lube for oxygen service should be used for combustion supporting atmosphere like oxygen, nitrous oxide and perhaps extremely high pressure air. Clean for oxygen service is the CGA recommended practice for high pressure compressed air.
Air at 4,500 psi can support combustion in a way that couldn't happen at ordinary shop air pressures.
Cleaned for oxygen service and using oxygen service rated everything is one way. Using nitrogen is another.
It doesn't appear that Dow 33 is oxygen service approved.
For the above incident, OSHA should have investigated and slapped the field with a serious fine.